I started with this recipe, but with a more curry powder, and a whole lot less honey--like maybe a 1/4tsp, at the most.
http://www.thekitchenmaus.com/quick-curry-ketchup/
I also don't mix it in a separate container. I just buy a smaller bottle of our usual and squirt some out into the existing family-size bottle of the same, to make room for the additives. I then use a funnel to feed the adds as a slurry, stir it with a chopstick or something, then shake the shit out of it. takes a day or two to settle in and taste right.
what's funny to me is she's trying to replicate Hela off-the-shelf curry ketchup. but I'd never had it until I stumbled upon it somewhere, after having made my own a few times. the Hela stuff was disgusting. part of it may be the too-sweetness, but it might also be the ketchup base they use, which everyone has their own favorite.
in the process, I figured out how to make my own Hut's hickory sauce, which I think is just ketchup with some liquid smoke and worcestershire. but I mess with that, too, as my memory changes.